Vibration absorbing pipe

ABSTRACT

A vibration-absorbing tube includes a bellows composed of a thin metal and a fiber braid reinforcement covering the bellows. The outer face of the bellows is covered (filled) with a buffer material, or rubber, from the bottom of troughs of the bellows to a height that is 0.5 to 2.0 times the height of ridges of the bellows, and the fiber braid reinforcement has a braided angle of 30° to 50°, preferably, of 35° to 45°. Gaps in the fiber braid reinforcement may be impregnated with a curable resin or rubber.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to vibration-absorbing tubes used inrefrigerant systems of air conditioners, dehumidifiers, refrigerators,and the like provided with compressors, which generate vibration, orused in other piping systems which generate vibration. Morespecifically, the present invention relates to vibration-absorbing tubesfor carbon dioxide refrigerant systems of automotive air conditioners.

2. Description of the Related Art

In general, straight pipes made of aluminum or copper are used forpiping for refrigerant systems of air conditioners, dehumidifiers,refrigerators, and the like. These pipes may resonate with the vibrationfrom compressors to generate noise. In order to suppress the resonance,a flexible vibration-absorbing tube having a bellows at the center ofthe tube is partially used in the piping.

The bellows provided to the flexible vibration-absorbing tube moderatelyexpands and contracts in response to the repeated pressure ofrefrigerant sent from the compressor and the vibration of thecompressor. Thus, the vibration is absorbed to prevent the pipe fromresonating. If the bellows wall is thick, its flexibility decreases.Therefore, the bellows cannot sufficiently absorb the vibration becauseof the difficulty in expansion and contraction. Furthermore, the stressis concentrated in a limited area of the bellows and fatigue failureoccurs in a short period of time. Accordingly, thinner bellows wall isfabricated so as to maintain the flexibility. However, too thin bellowswall has reduced pressure resistance.

Many suggestions have been presented in order to enhance the pressureresistance of the bellows while the bellows maintains the flexibility bykeeping an appropriate thickness. A non-extensible braided tube or arubber cover is provided on the periphery of the bellows asreinforcement (see Japanese Unexamined Patent Application PublicationNos. 10-318479, 6-281294, 7-159002, and 2001-182872).

With respect to the refrigerant for air conditioners, dehumidifiers,refrigerators, and the like, there is a strong demand for using naturalrefrigerant carbon dioxide (CO₂) which is an alternative to thecurrently used materials, i.e. chlorofluorocarbon which is responsiblefor global environmental problems such as destroying the ozone layer.

When the CO₂ refrigerant is used, the pressure in the piping for therefrigerant system reaches more than ten times that of when aconventional refrigerant is used.

Therefore, the above-mentioned vibration-absorbing tube merely providedwith a reinforcement such as the non-expandable braided tube or rubbercover cannot stand such high pressure, while maintaining effectivevibration absorption that prevents the pipe from resonating.

Another suggestion is presented. The bellows is strained in advance bydisposing an elastomer or the like between the braid and a joint of theinner tube and between the braid and the bellows, and the bellows isthen fastened to a socket by caulking. Thus, concaves of the bellows ofthe vibration-absorbing tube are partially filled with the elastomer(see PCT Japanese Translation Patent Publication No. 2002-544460).

In this vibration-absorbing tube, only an extremely narrow region, i.e.the ends of the bellows where the socket resides, is filled with theelastomer. Furthermore, the amount of the elastomer at the region isinsufficient because the elastomer extends toward the center from theregion during the caulking. Therefore, the vibration-absorbing tubecannot have a sufficient durability under such a high pressure.

Japanese Unexamined Patent Application Publication No. 2000-337572discloses a vibration-absorbing tube having high pressure resistance ofthe CO₂ refrigerant system. In this vibration-absorbing tube, metal meshcovers the bellows to enhance the strength, and the gap between thebellows and the metal mesh is filled with incompressible plastic toprevent the bellows from wearing caused by the metal mesh.

The vibration-absorbing tube reinforced by covering the bellows with themetal mesh has high pressure resistance, however, it is highly probablethat the intended purpose, i.e. the absorption of vibration, is notsatisfied. Recently, a layout of piping in an automobile enginecompartment has been highly restricted. Consequently, avibration-absorbing tube, as well as aluminium piping, should be used ata moderately curved state. Since the vibration-absorbing tube having thebellows covered with metal mesh is highly stiff and is less flexible, itis practically impossible to use the vibration-absorbing tube in acurved state for a refrigerant system of an automotive air conditioner.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide avibration-absorbing tube that maintains a high durability for long lifewhile being superior in vibration absorption. This vibration-absorbingtube can be partly used in piping for a high-pressured fluid such as aCO₂ refrigerant system even when the vibration-absorbing tube ismoderately curved.

A vibration-absorbing tube of the present invention includes a bellowscomposed of a thin metal and a fiber braid reinforcement covering thebellows. The vibration-absorbing tube further includes a buffer materialcovering the outer face of the bellows from the bottom of the troughs ofthe bellows to a height that is 0.5 to 2.0 times the height of ridges ofthe bellows. The fiber braid reinforcement has a braided angle, which isdetermined by the tilt angle of the fiber from the axis of the bellows,in the range of 30° to 50°.

Since the outer face of the bellows of the vibration-absorbing tubeaccording to the present invention is covered (filled) with the buffermaterial from the bottom to a predetermined height of the troughs of thebellows, the bellows exhibits improved vibration absorbency.Consequently, the vibration-absorbing tube can absorb vibration with abroader frequency spectrum and higher energy intensity. In order toyield sufficient vibration absorbency, the bellows should be covered(filled) with the buffer material from the bottom up to a height of 0.5times or more the height of the ridges of the bellows. Furthermore,instead of a reinforcing metal layer (mesh), since the fiber braidreinforcement is used in the vibration-absorbing tube of the presentinvention, wearing of the bellows caused by the reinforcing layer issufficiently prevented. Consequently, the troughs of the bellows are notnecessarily required to be entirely filled with the buffer material sothat the buffer material thickly covers over the ridges of the bellows.Contrarily, a thicker buffer material decreases pressure resistance, asdescribed in Examples below. Therefore, the thickness of the buffermaterial from the bottom of the troughs should be 2.0 times or less theheight of ridges of the bellows.

When an inner pressure is applied to the bellows, the rate of expansionin the longitudinal direction is larger than that of contraction in theradial direction due to its structure in comparison with a case of aconventional rubber hose used as a vibration-absorbing tube. Since thefiber braid reinforcement of the vibration-absorbing tube of the presentinvention has a braided angle in the range of 30° to 50°, the resistanceagainst expansion in the longitudinal direction of the bellows increasesand the durability is improved. When the braided angle is 50° or less,the durability is sufficiently improved. However, when the braided angleis less than 30°, the expansion in the radial direction of the bellowscannot be prevented. Furthermore, it is difficult to braid such a fiberbraid with conventional braiding machines. Therefore the conventionalbraiding machines are required to change in design. This leads to a highcost. As a result, the braided angle should be in the range of 30° to50°. Preferably, the braided angle is in the range of 35° to 45°.

In the present invention, a resin or rubber is applied to the fiberbraid reinforcement to penetrate and then it is cured. Therefore, evenif the vibration-absorbing tube is used in a curved state, the buffermaterial is not discharged from the troughs of the bellows. As a result,the buffer material does not migrate into gaps between fibers of thefiber braid reinforcement, the fiber displacement of the fiber braidreinforcement does not occur, and the high durability is kept for a longperiod of time.

Preferably, the resin or rubber that penetrates the fiber braidreinforcement has a low viscosity and readily penetrates the gapsbetween the fibers during the impregnation, and has comparatively highhardness and low deformation (expansion and contraction) after curing.Examples of the resin include urea resins, melamine resins, phenolresins, epoxy resins, vinyl acetate resins, cyanoacrylate resins,polyurethane resins, maleic acid resins, isocyanate resins, acrylicresins, and a mixture thereof. Examples of the rubber includechlorinated rubbers, acrylic (ACM) rubbers, hydrogenated nitrile rubbers(H-NBRs), epichlorohydrin (ECO) rubbers, butyl rubbers (IIRs),chlorosulfonated polyethylene (CSM) rubbers, chlorinated polyethylene(CM) rubbers, and a mixture thereof.

The fiber braid reinforcement does not necessarily include the curedresin or rubber. Alternatively, for example, at least one additionalfiber braid reinforcement disposed at the outside of the fiber braidreinforcement can prevent the innermost fiber braid reinforcement fromdisplacing the fibers.

Examples of fibers for the fiber braid reinforcement include acrylicfibers, novoloid fibers, carbon fibers, polyester fibers, vinylonfibers, silk, nylon fibers, polyamide fibers, polyparaphenylbenzobisoxazole (PBO) fibers, and aramid fibers. In particular, aramidfibers, which are excellent in heat resistance, are preferable becausethe temperature in the CO₂ refrigerant system reaches about 180° C.

Preferably, the cross section in the axis direction of the bellows is asequence of Ω-shapes or U-shapes. In such a shape, the bellows yields aflexibility and high absorbency of vibration. The Ω-shaped cross sectionis superior to the U-shaped cross section in flexibility, so the bellowshaving the Ω-shaped cross section is the most preferable.

Examples of the buffer material include polyisobutylene, ACM rubbers,H-NBRs, ECO rubbers, IIRs, CSM rubbers, CM rubbers, and a mixturethereof.

The vibration-absorbing tube of the present invention exhibits highlyimproved whip resistance and pressure resistance, as well as vibrationabsorbency. Therefore, the vibration-absorbing tube can be disposedpartially in piping for CO₂ refrigerant system or the like in a curvedstate and has a long service life.

Since the vibration-absorbing tube of the present invention has highvibration absorbency, whip resistance, and pressure resistance, thevibration-absorbing tube can be used in piping for a high-pressure fluidsuch as hydrogen gas, liquefied petroleum gas, and liquefied naturalgas, in addition to CO₂ refrigerant system, and exhibits high qualityfor a long time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial longitudinal cross-sectional view of thevibration-absorbing tube according to an embodiment of the presentinvention;

FIG. 2 is a longitudinal cross-sectional view particularly illustratinga part of the vibration-absorbing tube according to an embodiment of thepresent invention;

FIG. 3 is a longitudinal cross-sectional view particularly illustratinga part of the vibration-absorbing tube according to another embodimentof the present invention;

FIG. 4 schematically illustrates the vibration absorbency test; and

FIG. 5 schematically illustrates the whip resistance test.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be describedwith reference to figures.

A vibration-absorbing tube according to an embodiment of the presentinvention is partially disposed in piping for a CO₂ refrigerant system.Namely, the vibration-absorbing tube is disposed in series between pipesmade of aluminium, stainless steel, or the like constituting the piping.As shown in FIGS. 1 and 2, the vibration-absorbing tube 1 includes abellows 2, straight pipe units 6 integrated with both ends of thebellows 2, and nipples 7 fixed to the straight pipe units 6.

The bellows 2 has a plurality of ridges each independently forming aring. The cross section (longitudinal section) in the axial direction ofthese ridges is usually a U-shape (not shown) or an Ω-shape (see FIGS. 1and 2). The U-shaped bellows yields a high durability against expansionand contraction, and the Ω-shaped bellows yields a further higherdurability.

Preferably, troughs of the bellows 2 have an external diameter (namely,external diameter of the original pipe) of 3 to 13 mm. The diameter isdetermined in this range according to the fluid volume and pressure in apiping provided with the vibration-absorbing tube 1, the mechanicalquality and thickness of the material used for the bellows 2, and so on.

Preferably, the thickness of the bellows 2 is determined to be in therange of 0.1 to 0.3 mm according to the external diameter of the troughof the bellows 2 and the mechanical quality of the material.

A small number of the ridges of the bellows 2 decreases vibrationabsorbency. A large number of the ridges requires a longvibration-absorbing tube 1; hence, the cost for forming the bellows 2increases and the installation of the vibration-absorbing tube 1 to therefrigerant system is restricted. The number of the ridges of thebellows 2 is determined within the range from about 10 to about 300according to the mechanical quality and thickness of the material of thebellows 2, the external diameter of the trough, working and fluctuatingpressures at the portion where the bellows 2 is installed, and so on.

Preferably, the material of the bellows 2 is austenite stainless steel.For example, austenite stainless steel SUS304, SUS310, and SUS316 arepreferable. In particular, SUS316L stainless steel, excellent inmechanical properties such as tensile strength and ductility capacityand also having a high corrosion resistance, is most preferable.

The bellows 2 of the vibration-absorbing tube 1 of the present inventioncan be formed by a known single-ridge hydroforming.

After the forming the bellows 2, the nipples 7 (each having anintegrated base-ring 8 at the end) are formed by hard soldering on outerfaces of both ends of the bellows 2, and then the outer face of thebellows 2 is covered (filled) with a buffer material 3. In the methodfor covering (filling) the outer face of the bellows 2 with the buffermaterial 3, a pipe having an inner diameter of approximately the same asor slightly larger than the outer diameter of the bellows 2 and beingsplit into two pieces in the longitudinal direction can be used: eachpiece of the pipe is filled with a sufficient amount of the buffermaterial 3, for example, rubber; the bellows 2 is sandwiched betweenthese pieces of the pipe and these are left for a predetermined periodof time for hardening the buffer material 3; and then the pieces of thepipe are removed. In this method, all the troughs of the bellows 2 arefilled with the buffer material 3 and an excess amount of buffermaterial 3 spilling over the height H of the ridges covers the entireouter face of the bellows 2. When the thickness t of the buffer material3 covering the outer face of the bellows 2 is large, the pressuredurability decreases. Therefore, the thickness of the buffer material 3covering the outer face is required to be as small as possible.

In the present invention, that the outer face of the bellows 2 iscovered (filled) with the buffer material 3 does not mean that theentire outer face including the ridges is covered with the buffermaterial 3. The troughs should be filled with the buffer material 3 fromthe bottom to a predetermined height of the troughs. Furthermore,substantially all of the troughs disposed in the axial direction of thebellows 2 must be filled with the buffer material 3 up to thepredetermined level. Preferably, all of the troughs are filled with thebuffer material 3 up to substantially the same level of the troughs.

After the outer face of the bellows 2 is covered (filled) with thebuffer material 3, as shown in FIGS. 1 and 2, the circumference of thebellows 2 is covered with a fiber braid reinforcement 4. The fiber braidreinforcement 4 is a braided tubular material composed of, for example,acrylic fibers, novoloid fibers, carbon fibers, polyester fibers,vinylon fibers, silk, nylon fibers, polyamide fibers, or aramid fibers.Preferably, the braided angle θ (which is determined by the tilt angleof the fiber from the axis of the bellows) is in the range of 30° to50°, more preferably, in the range of 35° to 45° C., which is smallerthan the range of 54.8° to 56.8° for conventional fiber braidreinforcements of rubber hoses.

After the fiber braid reinforcement 4 is braided, the fiber braidreinforcement 4 may be impregnated with a resin, for example, with anepoxy resin and be left for a predetermined period of time for curingthe resin. The resin can protect the fiber braid reinforcement 4 fromfiber displacement even when the vibration-absorbing tube 1 is used in acurved state. Therefore, the bellows 2 can maintain the high durabilityfor a long period of time.

Each end of the fiber braid reinforcement 4 is fixed by clamping with areinforcement ring (clamping attachment) 9 on a base ring 8 integratedwith the end of the nipple 7, and thus the vibration-absorbing tube 1 ofthe present invention is fabricated.

The effect of the present invention will now be verified with referenceto examples.

EXAMPLE 1

A bellows 2 having a length of 374 mm and an external diameter of 11.2mm (having a height H of the ridge of the bellows of 1.63 mm) was madefrom an original stainless steel pipe having an external diameter of7.94 mm and a thickness of 0.18 mm by a hydraulic forming process. Astainless steel nipple 7 having a length of 50 mm and a thickness of1.03 mm was formed on the outer face of each end of the bellows 2 byhard soldering. The outer face of the bellows 2 was covered (filled)with an acrylic rubber, which functions as a buffer material 3,according to a process using the above-mentioned pipe split into twopieces. The inner diameter of the pipe split into two pieces was 0.2 mmlarger than the external diameter of the bellows 2, so that the acrylicrubber covering the outer face over the height H of ridges of thebellows 2 had a thickness t of 0.1 mm, i.e. 1.06 times the height H ofthe ridge of the bellows. A fiber braid reinforcement 4 was formed onthe outer face of the bellows by braiding aramid fiber at a braidedangle of 40°. The fiber braid reinforcement 4 was not impregnated withrubber in these Examples (see FIGS. 1 and 2).

EXAMPLE 2

After covering (filling) the outer face of the bellows 2 with an acrylicrubber as in Example 1, the acrylic rubber covering the outer face overthe height H of ridges of the bellows 2 was slit in the axis directionof the bellows 2 and was then peeled from the outer face of the bellows2 so that the acrylic rubber, i.e. the buffer material 3, remained onlyat the portions of the troughs lower than the narrowest parts 5 betweenthe adjacent Ω-shaped ridges. The fiber braid reinforcement 4 was formedby braiding aramid fiber at a braided angle of 40° on the outer face ofthe bellows 2. The fiber braid reinforcement 4 was not impregnated withrubber in this Example (see FIG. 3).

EXAMPLE 3

As in Example 1, bellows 2 each having a length of 374 mm and anexternal diameter of 11.2 mm (having a height H of ridge of the bellowsis 1.63 mm) were made from an original stainless steel pipe having anexternal diameter of 7.94 mm and a thickness of 0.18 mm by a hydraulicforming process. A stainless steel nipple 7 having a length of 50 mm anda thickness of 1.03 mm was formed on each outer end face of each bellows2 by hard soldering. The outer face of the bellows 2 was covered(filled) with an acrylic rubber, which functions as a buffer material 3,according to the process using the above-mentioned pipe split into twopieces. In this Example, the inner diameters of the pipes split into twopieces were 0.2 to 4 mm larger than the external diameter of the bellows2, so that the acrylic rubber covering the outer face over the height Hof ridges of each bellows 2 had a thickness t of 0.1 to 2 mm, i.e. about1.06 to 2.23 times the height H of the ridges of the bellows. A fiberbraid reinforcement 4 was formed on each outer face of the bellows bybraiding aramid fiber at braided angles of 45° to 35°. An acrylic rubberdissolved in a solvent was applied to each fiber braid reinforcement 4to sufficiently penetrate the fiber braid reinforcement 4, and was thencured by heating at 180° C. for 30 minutes (see FIGS. 1 and 2).

COMPARATIVE EXAMPLE 1

As an equivalent of a known vibration-absorbing tube, a bellows wasformed as in Example 1, and a stainless steel nipple was formed on theouter face of each end of the bellows by hard soldering. Withoutcovering with a buffer material, a fiber braid reinforcement was formeddirectly by braiding on the outer face of the bellows at a braided angleof 54.7°. The fiber braid reinforcement was not impregnated with arubber.

COMPARATIVE EXAMPLE 2

A vibration-absorbing tube was formed as in Comparative Example 1, butthe fiber braid reinforcement was formed by braiding at a braided angleof 40° instead of 54.70 in Comparative Example 1.

Vibration absorbency, whip resistance, and pressure resistance wereevaluated for several vibration-absorbing tubes fabricated in Examples 1to 3 and Comparative Examples 1 and 2, respectively.

These evaluation tests were conducted under the following conditions:

-   1. Vibration absorbency test (see FIG. 4)    -   Setting of the vibration-absorbing tubes: straight    -   Inner pressure (gauge pressure): 11 MPa (constant)    -   Temperature: ambient    -   Excitation direction: vertical    -   Vibration amplitude: ±0.06 mm    -   Frequency: from 40 Hz to 450 Hz    -   cycle: 10 minnute-   2. Whip resistance test (see FIG. 5)    -   Setting of the vibration-absorbing tubes: curved up to 90° with        a radius of 220 mm    -   Inner pressure (gauge pressure): 11 MPa (constant)    -   Temperature: ambient    -   Vibration amplitude: ±15 mm    -   Speed of rotation: 450 rpm-   3. Pressure resistance test (not shown in the figure)    -   Setting of the vibration-absorbing tubes: turned up by 180° with        a radius of 90 mm    -   Inner pressure (gauge pressure): 0 to 15 MPa or 0 to 21 MPa    -   Temperature: 130° C.    -   Repeating speed (Frequency): 30 cpm (0.5 Hz)    -   Working fluid: refrigerant oil

The results are shown in Table I. The vibration absorbency is expressedby the average of differences (dB) calculated from vibration intensitiesmeasured through pickups at both the input and at the output for eachfrequency in the vibration absorbency test. A larger absolute valuemeans a higher vibration absorbency. The whip resistance is expressed bya period of time when causing deformation or breakage ofvibration-absorbing tubes in the whip resistance test. The pressureresistance is expressed by the number of pressure application cyclesuntil causing breakage of vibration-absorbing tubes in the pressureresistance test. In Table I, “A” in Examples 1 to 3 means that theperformance is highly improved compared with that of the conventionalvibration-absorbing tube, and “B” in Examples 1 to 3 means theperformance is the same as or inferior to that of the conventionalvibration-absorbing tube.

The results of Samples 3 and 4 shown in Table I exhibit thatvibration-absorbing tubes, each including a buffer material and a fiberbraid reinforcement according to the present invention, were highlyimproved in vibration absorbency, whip resistance, and pressureresistance compared with Comparative Example 1 (Sample 1). Withcomparison between Samples 3 and 4, the vibration-absorbing tubeincluding the buffer material having a smaller thickness of a rangedefined in the present invention was highly improved in pressureresistance between 0 and 21 MPa, though the vibration absorbencyslightly decreased.

The results of Samples 5, 6, 9, and 10 exhibit that vibration-absorbingtubes, each including a fiber braid reinforcement filled with rubberaccording to the present invention, were highly improved in vibrationabsorbency, whip resistance, and pressure resistance compared withComparative Example 1 (Sample 1). In particular, with comparison betweenSamples 3 and 4, it was observed that the vibration-absorbing tubeincluding the fiber braid reinforcement filled with rubber was highlyimproved in pressure resistance between 0 and 21 MPa, though thevibration absorbency slightly decreased.

The pressure resistance between 0 and 15 MPa was improved in Sample 2.However, the result of Sample 2 exhibits that a vibration-absorbing tubewith no buffer material was not improved in vibration absorbency andwhip resistance, although the vibration-absorbing tube included a fiberbraid reinforcement with a braided angle of a range defined in thepresent invention, which was smaller than that of comparative Example 1(Sample 1). The vibration absorbency was improved in Sample 7. However,the result of Sample 7 exhibits that the vibration-absorbing tubeincluding the buffer material of an excess thickness over a rangedefined in the present invention reduced the whip resistance and thepressure resistance, although the vibration-absorbing tube included afiber braid reinforcement with a braided angle of a range defined in thepresent invention and also the fiber braid reinforcement was impregnatedwith rubber. The whip resistance was improved in Sample 8. However, theresult of Sample 8 exhibits that the vibration-absorbing tube includingthe fiber braid reinforcement with a braided angle of outside of therange defined in the present invention was not sufficiently improved invibration absorbency and pressure resistance, although the buffermaterial had a thickness of a range defined in the present invention andwas filled with rubber.

Reinforcing layers after the tests showed good performance withoutwearing in all of the samples. TABLE I Buffer Material Pressure PressureThickness from Height of buffer Fiber braid reinforcement Vibration Whipresistance resistance the ridge of material relative Braided Impregnatedabsorbency resistance [0 to 15 MPa] [0 to 21 MPa] Sample bellows (mm) toH (mm) angle (°) with rubber (dB) (h) (time) (time) Comparative 1 0 054.7 Not  −6.9: B   0.1-0.2:  70,000:  26,000: Example 1 impregnated B BB Comparative 2 0 0 40.0 Not  −7.1: B   0.1-0.2: >200,000:  67,000:Example 2 impregnated B A B Example 1 3 0.1 1.06 H 40.0 Not −10.8:A  >200: >200,000:  30,000: impregnated A A B Example 2 4 Under the 0.67H 40.0 Not −9.5: A >200: >200,000: >100,000: narrowest parts impregnatedA A A of the bellows Example 3 5 0.1 1.06 H 40.0 Impregnated −9.3:A >200: >200,000: >100,000: A A A 6 1.0 1.61 H 40.0 Impregnated −9.0:A >200: >200,000: >100,000: A A A 7 2.0 2.23 H 40.0 Impregnated −9.1: A2-3:  100,000:  60,000: B B B 8 0.1 1.06 H 54.7 Impregnated −8.1:A >200:  90,000:  50,000: A B B 9 0.1 1.06 H 45.0 Impregnated −8.9:A >200: >200,000: >100,000: A A A 10 0.1 1.06 H 35.0 Impregnated −10.1:A  >200: >200,000: >100,000: A A A

1-8. (canceled)
 9. A vibration-absorbing tube comprising: a bellowscomposed of a thin metal and having troughs and ridges; a fiber braidreinforcement covering the bellows and having a braided angle of 30° to50°; and a buffer material covering the outer face of the bellows fromthe bottom of the troughs to a height that is 0.5 to 2.0 times theheight of ridges.
 10. The vibration-absorbing tube according to claim 9,wherein gaps in the fiber braid reinforcement are impregnated with acurable resin or rubber composition.
 11. The vibration-absorbing tubeaccording to claim 10, wherein the resin composition comprises at leastone resin selected from the group consisting of urea resins, melamineresins, phenol resins, epoxy resins, vinyl acetate resins, cyanoacrylateresins, polyurethane resins, maleic acid resins, isocyanate resins, andacrylic resins.
 12. The vibration-absorbing tube according to claim 10,wherein the rubber composition comprises at least one rubber selectedfrom the group consisting of chlorinated rubbers, acrylic rubbers,hydrogenated nitrile rubbers, epichlorohydrin rubbers, butyl rubbers,chlorosulfonated polyethylene rubbers, and chlorinated polyethylenerubbers.
 13. The vibration-absorbing tube according to claim 9 furthercomprising at least one additional fiber braid reinforcement at theoutside of the fiber braid reinforcement.
 14. The vibration-absorbingtube according to claim 9, wherein the fibers constituting the fiberbraid reinforcement and the additional fiber braid reinforcement areselected from the group consisting of acrylic fibers, novoloid fibers,carbon fibers, polyester fibers, vinylon fibers, silk, nylon fibers,polyamide fibers, polyparaphenylene benzobisoxazole fibers, and aramidfibers.
 15. The vibration-absorbing tube according to claim 9, whereinthe cross section of the bellows has a sequence of S2-shapes orU-shapes.
 16. The vibration-absorbing tube according to claim 14,wherein the cross section of the bellows has a sequence of S2-shapes orU-shapes.
 17. The vibration-absorbing tube according to claim 9, whereinthe buffer material is a rubber composition comprising at least onerubber selected from the group consisting of polyisobutylene, acrylicrubbers, hydrogenated nitrile rubbers, epichlorohydrin rubbers, butylrubbers, chlorosulfonated polyethylene rubbers, and chlorinatedpolyethylene rubbers.
 18. The vibration-absorbing tube according toclaim 14, wherein the buffer material is a rubber composition comprisingat least one rubber selected from the group consisting ofpolyisobutylene, acrylic rubbers, hydrogenated nitrile rubbers,epichlorohydrin rubbers, butyl rubbers, chlorosulfonated polyethylenerubbers, and chlorinated polyethylene rubbers.
 19. Thevibration-absorbing tube according to claim 15, wherein the buffermaterial is a rubber composition comprising at least one rubber selectedfrom the group consisting of polyisobutylene, acrylic rubbers,hydrogenated nitrile rubbers, epichlorohydrin rubbers, butyl rubbers,chlorosulfonated polyethylene rubbers, and chlorinated polyethylenerubbers.
 20. The vibration-absorbing tube according to claim 16, whereinthe buffer material is a rubber composition comprising at least onerubber selected from the group consisting of polyisobutylene, acrylicrubbers, hydrogenated nitrile rubbers, epichlorohydrin rubbers, butylrubbers, chlorosulfonated polyethylene rubbers, and chlorinatedpolyethylene rubbers.
 21. The vibration-absorbing tube according toclaim 9, wherein the vibration-absorbing tube is partially disposed inpiping for a carbon dioxide refrigerant system, hydrogen gas, liquefiedpetroleum gas, chlorofluorocarbon refrigerant, or liquefied natural gas.22. The vibration-absorbing tube according to claim 14, wherein thevibration-absorbing tube is partially disposed in piping for a carbondioxide refrigerant system, hydrogen gas, liquefied petroleum gas,chlorofluorocarbon refrigerant, or liquefied natural gas.
 23. Thevibration-absorbing tube according to claim 15, wherein thevibration-absorbing tube is partially disposed in piping for a carbondioxide refrigerant system, hydrogen gas, liquefied petroleum gas,chlorofluorocarbon refrigerant, or liquefied natural gas.
 24. Thevibration-absorbing tube according to claim 16, wherein thevibration-absorbing tube is partially disposed in piping for a carbondioxide refrigerant system, hydrogen gas, liquefied petroleum gas,chlorofluorocarbon refrigerant, or liquefied natural gas.
 25. Thevibration-absorbing tube according to claim 17, wherein thevibration-absorbing tube is partially disposed in piping for a carbondioxide refrigerant system, hydrogen gas, liquefied petroleum gas,chlorofluorocarbon refrigerant, or liquefied natural gas.
 26. Thevibration-absorbing tube according to claim 18, wherein thevibration-absorbing tube is partially disposed in piping for a carbondioxide refrigerant system, hydrogen gas, liquefied petroleum gas,chlorofluorocarbon refrigerant, or liquefied natural gas.
 27. Thevibration-absorbing tube according to claim 19, wherein thevibration-absorbing tube is partially disposed in piping for a carbondioxide refrigerant system, hydrogen gas, liquefied petroleum gas,chlorofluorocarbon refrigerant, or liquefied natural gas.
 28. Thevibration-absorbing tube according to claim 20, wherein thevibration-absorbing tube is partially disposed in piping for a carbondioxide refrigerant system, hydrogen gas, liquefied petroleum gas,chlorofluorocarbon refrigerant, or liquefied natural gas.